CN115023532B

CN115023532B - Method and drill bit for sealing walls of a borehole

Info

Publication number: CN115023532B
Application number: CN202080074888.7A
Authority: CN
Inventors: L·坦斯卡宁; T·坦斯卡宁
Original assignee: L&t Mining Solutions Ltd
Current assignee: L&t Mining Solutions Ltd
Priority date: 2019-10-30
Filing date: 2020-10-27
Publication date: 2024-05-14
Anticipated expiration: 2040-10-27
Also published as: AU2020374403A1; CL2022001036A1; US20220389790A1; EP3816394A1; CN115023532A; EP3816394B1; EP3816394C0; CA3155684A1; WO2021083865A1; ZA202204217B

Abstract

A method and drill bit (11) for sealing a borehole wall (31) are disclosed. The method comprises drilling a blasthole in rock by means of a drill bit (11) connected to a hollow drill rod (10); flushing the drill bit (11) and the hollow drill rod (10) via at least one flushing orifice (19); providing a sealant to the hollow drill rod (10); and releasing the sealant to the borehole wall (31) while lifting the drill bit (11). The drill bit (11) comprises a flushing orifice (19) and a sealant orifice (12), wherein the flushing orifice (19) is below the sealant orifice (12); and the method comprises covering the flushing ports (19) after the completion of drilling the blastholes; -providing the sealant to the drill bit (11); and releasing the sealant via the sealant orifice (12) while lifting the drill bit (11).

Description

Method and drill bit for sealing walls of a borehole

Background

In mining and rock excavation, blastholes may be drilled in rock and filled with solid, granular, slurry, gel, emulsion or liquid explosives. For example, liquid explosives are pumped into blastholes and controllably detonated. The amount of rock cracking or rock breaking may be controlled by the amount of explosive material inserted into the blastholes. The blastholes may be continuously drilled and detonated to further control the direction of the fracture.

Sometimes, the rock will have natural fractures that are not visible to the driller. Successive blasts may cause further rock breakage. Superficially, the location, direction, or magnitude of the fracture extending from the borehole wall may not be predicted. The blasthole drilling process may cause further rock fracture or cracking. When the blasthole is filled with explosives, at least a portion of the explosives may enter the fracture. This makes controlled rock blasting more difficult. When detonating explosives, rock may fracture uncontrollably along a fracture extending from the borehole wall.

Additionally or alternatively, the borehole wall may contain small fragments that are crushed during drilling. As the drill is lifted, the chips may fall deeper into the borehole and fill the bottom of the borehole. The chips, small particles or sand may create obstructions that block the feed tube configured to fill the blasthole with explosives. To complete the filling of the blasthole, the feed tube must be lifted from the blasthole and the drill assembly must be reinserted to clear the blasthole bottom. Sometimes, the cleaning process must be repeated several times, resulting in waste of time and resources.

The walls of the cannon may be covered with a tubular liner, or drill pipe may be used to provide a concrete paste for covering the walls. EP0777018A1 discloses a method for producing concrete coated in a hole by supplying a liquid or pasty concrete material to a set of nozzles via a pipe arranged in a drill pipe and discharging the substance from an opening in the drill pipe into the hole. The material solidifies as the drill bit is lifted from the hole.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

Methods and drill bits for sealing a borehole wall are disclosed. The drill pipe may include a plurality of successive sections that are added to the drill pipe as drilling proceeds. The drill pipe is hollow, allowing drilling fluid to pass through the drill pipe to the drill bit. Drilling fluids flush the drill bit and borehole during drilling.

After the borehole has been drilled to the desired depth, drilling fluid is flushed from the drill pipe. The drill bit includes a flushing port for flushing the blasthole and a sealant port. The flush aperture is covered by the article, leaving the sealant aperture open. The object may be a spherical portion that falls into the hollow drill pipe when the drill assembly is at a desired depth.

The sealant is provided into the drill pipe and pushed toward the drill bit. The sealant cannot pass through the blocked flush orifice, it actually flows through the sealant orifice outside the drill bit and into the borehole wall. The sealant orifice is positioned higher in the drill bit than the flush orifice. The drill assembly is rotated while the sealant covers the borehole wall. Lifting the rotary drill assembly from the borehole, wherein the rotary drill bit shapes the borehole wall. Centrifugal force and pressure applied to the sealant cause the sealant to penetrate into the crack. The sealant includes sufficient viscosity to prevent sagging when the drilling assembly is lifted.

The sealant shapes the borehole wall to a desired shape and size. The borehole wall may be formed with the same equipment used in drilling without lifting the drill pipe from the borehole. The functionality is arranged in the drill bit. There are no special requirements for the drill rod assembly. The borehole operator can use standard drill pipe inventory, which reduces the number of errors and the need for different spare parts. The drill pipe is readily available from a number of suppliers.

Many of the attendant features will be more readily appreciated as the same becomes better understood by reference to the following detailed description considered in connection with the accompanying drawings. The examples described below are not limited to implementations that address any or all of the disadvantages of known blasthole drilling solutions.

Drawings

The specification will be better understood from a reading of the following detailed description taken in conjunction with the drawings in which

FIG. 1 illustrates a cross-sectional view of an exemplary embodiment of a drill bit connected to a drill rod;

FIG. 2 illustrates a cross-sectional view of an exemplary embodiment of a drill bit;

FIG. 3 illustrates a cross-sectional view of an exemplary embodiment of the interior of a borehole;

FIG. 4 illustrates a cross-sectional view of an exemplary embodiment of the interior of a borehole when the drill assembly is lifted; and

Fig. 5 schematically illustrates the steps of a method for drilling a blasthole.

In the drawings, like reference numerals are used to designate like parts.

Detailed Description

The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present examples may be constructed or utilized. However, the same or equivalent functions and sequences may be accomplished by different examples.

Although the current examples are described and illustrated herein as being implemented in a vertical blasthole formation, they are provided as examples and not as limitations. As will be appreciated by those skilled in the art, the present examples are suitable for application in a variety of different types of rock drilling applications.

Methods and drill bits for sealing a borehole wall are disclosed. FIG. 1 illustrates a cross-sectional view of an exemplary embodiment of a drill bit 11 coupled to a drill rod 10. In the present example, the connection is provided by female threads 16 provided to bit 11 and male threads 17 provided to drill pipe 10. Various alternatives for connecting drill bit 11 to drill pipe 10 may be employed without altering the scope of the present invention.

The drill pipe 10 is hollow. In this example, the hollow 15 is located in the middle of the drill rod 10. The hollow portion 15 allows flushing fluid to pass through the drill bit 11 and to at least one flushing port 19 arranged near the drill bit button 14. Drilling fluid is pumped to drill pipe 10. The drilling fluid provides hydrostatic pressure to prevent formation fluids from entering the borehole, keeps the drill bit 11 cool and clean during drilling, carries out cuttings, and pauses cuttings as drilling pauses and drilling assemblies pass into and out of the borehole. The flushing fluid may be a liquid, gas, water-based mud, non-aqueous mud, oil-based mud (OB); and gaseous drilling fluids, wherein a wide range of gases may be used.

Bit 11 includes at least one flushing port 19 and at least one sealant port 12. During drilling, a portion of the flushing fluid may also pass through the sealant orifice 12. The flushing ports 19 are blocked before the process of sealing the cell wall is started. In the present example, the flush aperture 19 is positioned below the sealant aperture 12 in the drill bit 11 while drilling downward. An upward, downward, lower, upper or higher direction is relevant to the current example. It will be apparent to those skilled in the art that drilling can be performed in any direction, wherein the orientation definition described herein will be transformed into the drilling direction.

FIG. 2 illustrates a cross-sectional view of an exemplary embodiment of bit 11. When bit 11 is connected to drill rod 10, bit 11 includes a cavity 13 below female threads 16. In the present embodiment, the sealant orifice 12 is arranged at the wall of the chamber 13, extending towards the cell wall. Inside the chamber 13 is a seat 18 configured to receive an article for blocking the flushing orifice 19. In one embodiment, the abutment 18 is directly below the hollow portion 15 of the drill rod 10. Articles such as spherical parts drop into the hollow portion 15 of the drill rod 10. The bulb portion 20 is visible in fig. 2 but not in fig. 1. The bulb 20 falls onto the seat 18 and blocks the flushing orifice 19. Alternatively, instead of dropping, the article may be pushed through the drill pipe 10 by pumping fluid into the drill pipe 10. This allows the article to pass through the drill pipe 10 at any angle. The support 18 is configured to match the shape of the article. The sealant may be pumped through drill pipe 10 to drill bit 11, where the sealant passes only through sealant orifice 12, not flush orifice 19.

FIG. 3 illustrates a cross-sectional view of an exemplary embodiment of the interior of a borehole. The rock mass has a fracture 30, some of which extend through the borehole wall 31. The crack 30 may naturally occur in the rock or a previous blast may have caused the crack 30 inside the rock mass. Sometimes, it is difficult to predict the shape, direction, or magnitude of the crack 30. In the blast hole firing method according to the prior art, the drilled blast hole is filled with solid, granular, slurry, gel, emulsion or liquid explosives. The explosive may enter the fracture 30 and cause an unexpected reaction upon detonation. The direction and influence of the blasting may cause further problems.

Alternatively or additionally, the drilling process may separate small fragments from the edges of the fracture 30, which fall to the bottom of the borehole when the drill assembly 10, 11 is lifted from the borehole. In one method, explosives are pumped into a borehole via a conduit inserted into the borehole. The tubing may not reach the bottom of the borehole due to the fragments blocking the passageway. When this is detected at the surface, the drill assembly 10, 11 must be reinserted into the blasthole to flush out the chips. This can be a very time consuming process.

In the present example, the drilling rig assemblies 10, 11 have completed drilling and reached the desired depth. The ball section 20 has been dropped from the surface onto the seat 18 via the drill rod 10 to block the flushing orifice 19. The sealant is pumped through the sealant orifice 12 toward the cell wall 31. The sealant begins to rise in the blast hole and into the fracture 30.

Fig. 4 illustrates a cross-sectional view of an exemplary embodiment of the borehole interior when the drill assembly 10, 11 is lifted. While lifting bit 11, the sealant is pumped through sealant orifice 12 and the drill assembly including drill pipe 10 and bit 11 is rotated. The sealant orifice 12 releases the sealant and the centrifugal force caused by the rotary drill bit pushes the sealant toward the borehole wall 31. The sealant enters deeper into the fracture 30 due to the pressure and centrifugal force provided by the pump configured to pump the sealant. The blocked fracture 40 does not cause problems during the later stages of pumping explosives into the borehole.

The diameter of the drill bit 11 is wider below the level of the sealant orifice 12 than at the level of the sealant orifice 12. In one embodiment, the diameter of bit 11 is widest below the level of sealant orifice 12. When the drill bit 11 is lifted and rotated along the borehole wall 31, the drill bit 11 shapes the borehole wall 31. Any excess sealant remains above bit 11. Thus, the blast hole wall 31 becomes the sealing wall 41 coated with the sealant.

In one embodiment, the object to be deployed into the hollow drill shaft 10 is a spherical section. The shape of the ball section 20 is suitable for passing through the hollow drill rod 10, as there are no edges that might interfere with travel. In one embodiment, the shape of the article may include edges and/or the article may include an elongated shape. In one embodiment, the article has a relative density greater than the sealant. In one embodiment, the bulb portion 20 has a relative density greater than the sealant. This prevents the article from rising from the seat 18 as the sealant is pumped to the drill bit 11. In one embodiment, bulb portion 20 is made of metal. The material of the article may be durable to withstand chemical stresses caused by the flushing fluid and/or the sealant; and mechanical stresses caused by the drilling environment. In one embodiment, bulbous portion 20 has a unique color to aid in visually locating bulbous portion 20 in a dirty environment.

Fig. 5 schematically illustrates the steps of a method for drilling a blasthole. In a first step 51, the method comprises drilling a blasthole in rock by means of a drill bit 11 connected to a hollow drill rod 10. Step 52 includes flushing bit 11 and the hollow drill shaft through at least one flushing port 19. Step 53 includes covering the flush hole 19 after drilling the borehole is completed. Step 54 includes releasing the sealant through the sealant orifice while lifting the drill bit 11.

A method for sealing a cell wall is disclosed. The method comprises the following steps: drilling a blasthole in rock by a drill bit connected to a hollow drill rod; flushing the drill bit and the hollow drill rod through the at least one flushing port; providing a sealant to the hollow drill stem; and releasing the sealant to the borehole wall while lifting the drill bit. The drill bit includes a flushing orifice and a sealant orifice, wherein the flushing orifice is below the sealant orifice; and the method includes covering the flush aperture after completion of drilling the borehole; providing a sealant to the drill bit; and releasing the sealant via the sealant orifice while lifting the drill bit. In one embodiment, the method includes rotating the drill bit while releasing the sealant through the sealant orifice, wherein centrifugal force pushes the sealant toward the borehole wall. In one embodiment, the diameter of the drill bit below the level of the sealant orifice is wider than the diameter at the level of the sealant orifice, wherein lifting the drill bit shapes the sealant along the borehole wall. In one embodiment, the method includes covering the lower flush aperture by dropping a spherical portion into the hollow drill stem, wherein the spherical portion has a relative density greater than the sealant. In one embodiment, the spherical portion is made of metal. In one embodiment, the drill bit includes a seat for the ball portion. In one embodiment, the drill bit includes a female thread for connecting the drill bit to the drill rod and a chamber below the female thread, wherein the sealant orifice opens into the chamber.

Alternatively or additionally, a drill bit for sealing a borehole wall is disclosed. The drill bit comprises a connection member for connection to a hollow drill rod; and a flush aperture, a sealant aperture positioned above the flush aperture; and a seat configured to receive from the drill pipe a blocking object for covering the flushing aperture; and wherein the drill bit is configured to receive the sealant from the drill pipe and to expel the sealant through the sealant orifice. In one embodiment, the drill bit diameter below the level of the sealant orifice is wider than the diameter at the level of the sealant orifice. In one embodiment, the occluding component is a spherical portion having a relative density greater than the sealant. In one embodiment, the spherical portion is made of metal. In one embodiment, the support is a support for a spherical portion. In one embodiment, the connection member comprises a female thread for connection to the drill rod and a chamber below the female thread, wherein the sealant orifice opens into the chamber.

Any range or device value given herein may be extended or altered without losing the effect sought.

Although at least a portion of the subject matter has been described in language specific to structural features and/or actions, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and acts described above are disclosed as example of implementing the claims, and other equivalent features and acts are intended to be within the scope of the claims.

It should be appreciated that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. Embodiments are not limited to those embodiments that solve any or all of the stated problems or those embodiments that have any or all of the stated benefits and advantages. It should be further understood that references to "an" item refer to one/one or more/multiple of those items.

The steps of the methods described herein may be performed in any suitable order, or simultaneously where appropriate. In addition, individual blocks may be deleted from any of the methods without departing from the spirit and scope of the subject matter described herein. Aspects of any of the examples described above may be combined with aspects of any of the other examples described to form other examples without losing the effect sought.

The term "comprising" is used herein to mean including the identified method blocks or elements, but such blocks or elements do not include an exclusive list, and the method or apparatus may include additional blocks or elements.

It should be understood that the above description is given by way of example only and that various modifications may be made by one skilled in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of accuracy or with reference to one or more individual embodiments, many modifications can be made to the disclosed embodiments by those skilled in the art without departing from the spirit or scope of the present disclosure.

Claims

1. A method for sealing a cell wall (31), comprising the steps of:

Drilling a blasthole in rock by means of a drill bit (11) connected to a hollow drill rod (10);

flushing the drill bit (11) and the hollow drill rod (10) via at least one flushing orifice (19);

providing a sealant to the hollow drill rod (10); and

Releasing the sealant to the borehole wall (31) while lifting the drill bit (11),

The method is characterized in that:

The drill bit (11) comprises a flushing orifice (19) and a sealant orifice (12), wherein the flushing orifice (19) is below the sealant orifice (12); and is also provided with

The method comprises covering the flushing ports (19) after the completion of drilling the blastholes;

-providing the sealant to the drill bit (11); and

Releasing the sealant via the sealant orifice (12) while lifting the drill bit (11).

2. The method according to claim 1, characterized by rotating the drill bit (11) while releasing the sealant via the sealant orifice (12), wherein centrifugal force pushes the sealant towards the blasthole wall (31).

3. The method according to claim 1 or claim 2, characterized in that the diameter of the drill bit (11) below the level of the sealant orifice (12) is wider than the diameter at the level of the sealant orifice (12), wherein lifting the drill bit (11) shapes the sealant along the blasthole wall (31).

4. Method according to claim 1 or claim 2, characterized in that a lower flushing orifice (19) is covered by dropping a spherical portion (20) into the hollow drill rod (10), wherein the spherical portion (20) has a greater relative density than the sealant.

5. The method according to claim 4, characterized in that the spherical portion (20) is made of metal.

6. A method according to claim 4, characterized in that the drill bit (11) comprises a seat (18) for the spherical portion (20).

7. Method according to claim 1 or claim 2, characterized in that the drill bit (11) comprises a female thread for connecting the drill bit (11) to the hollow drill rod (10) and a chamber (13) below the female thread, wherein the sealant orifice (12) opens into the chamber (13).

8. A drill bit for sealing a borehole wall (31), comprising:

A connecting member for connecting to a hollow drill rod (10); and

A flushing orifice (19),

Characterized in that the drill bit (11) comprises:

a sealant orifice (12) positioned higher than the flushing orifice (19); and

-A seat (18) configured to receive from the hollow drill rod (10) a blocking article for covering the flushing aperture (19); and wherein

The drill bit (11) is configured to receive a sealant from the hollow drill rod (10) and to expel the sealant through the sealant orifice (12).

9. Drill bit according to claim 8, characterized in that the diameter of the drill bit (11) below the level of the sealant orifice (12) is wider than the diameter at the level of the sealant orifice (12).

10. Drill bit according to claim 8 or 9, characterized in that the blocking object is a spherical portion (20) having a relative density greater than the sealant.

11. Drill bit according to claim 10, characterized in that the spherical portion (20) is made of metal.

12. Drill bit according to claim 10, characterized in that the abutment (18) is an abutment for the spherical portion (20).

13. Drill bit according to claim 8 or 9, characterized in that the connection member comprises a female thread for connection to the hollow drill rod (10) and a chamber (13) below the female thread, wherein the sealant orifice (12) opens into the chamber (13).